1. Field of the Invention
The present invention relates to an image reading device, and specifically relates to an image reading device and method for optically reading a document image through a glass document platen.
2. Description of the Related Art
In the field of conventional image reading devices, methods have been proposed for cleaning the glass document platen using a cleaner as a countermeasure for soiling or injury to the glass document platen caused by image reading by a stationary device. Specifically, Japanese Unexamined Patent Application No. HEI 5-122468 discloses an image reading device provided with a cleaning roller for cleaning the document reading area of the reading means and which is positioned so as to allow passage or stop said reading means outside the document placement region of a document platen and which rotatably drives said cleaning roller each predetermined number of scanning revolutions of said reading means so as to improve reading accuracy by preventing soiling of the document surface and preventing inadequate reading of a document image caused by soiling of the document reading surface of said reading means.
The aforesaid conventional image reading devices are disadvantageous insofar as when the glass surface of the document platen becomes soiled only a cleaning roller, cleaning sheet or the like is used to wipe the soiled glass surface, such that when a residue remains on said glass surface the reading of an image of a document cannot be adequately accomplished. A further disadvantages arises in that in order to avoid leaving a residue, a lengthy cleaning time is required as well as a complicated cleaning mechanism. A still further disadvantage arises when the glass surface itself of the document platen is damaged in that the cleaning will not remove the defect, and as a result, reading of an image of a document cannot be adequately accomplished.